KeyListener problems

Newbie & Debugging Questions
#1

Well, my KeyListener works, but I think its a bit odd how it does work. I just checked, and whenever I press a key, the keyPressed() method is called once, waits a bit, and then it continuously gets called. I know this is normal.

But, I just checked, and as keyPressed is called continuously, keyReleased is called contiuously too. It looks something like this:

keyPressed
–wait for a second–
keyPressed
keyReleased
keyPressed
keyReleased

Is that normal that keyReleased is being called? Sometimes, it comes up with problems, like if I am travelling down right in my game, a keyPressed event is skipped, so it no longer travels in a diagonal direction, either down or right. However, this happens randomly.

It only lasts for a very little time, but its very noticeable. Any tips on how to fix this? I think it might have something to do with me being on Ubuntu, and I’m on OpenJDK.

#2

Unfortunately that is the key-repeat from the OS, so nothing java can do about :confused: Afaik, the only way to overcome this issue is to use a lib with native bindings like JInput.

#3

huh, I guess I’ll do that.

#4

You could try key polling like what I did here:

net.phatcode.rel.utils/Keyboard class

http://rel.phatcode.net/junk.php?id=138

#5

I’ll try that, but it still will have the same problem. keyPressed and keyReleased are constantly called(one after eachother), and sometimes the keyPressed event misses a few calls, and the net effect is that the key is released.

I’ll see though, and update you if it works :slight_smile:

#6

Same problem I had with the callback mechanism of keylisteners. That’s why I poll my input. It’s easier to use too.

#7

Alright, I’m adding it in right now. Also, wouldn’t it be better if you just got an array for having the keyPress array? Isn’t it pointless to have a keysReleased array since keyPress and keyRelease both have opposite values(true and false), so you can just call !keysPressed[KEY] to get if it is released?

#8

You could try that but it won’t work with just one array. Hence the scanKeys() method.

#9

Dang, that helped me alot. Not only am I taking the input, I’m replacing my whole frame control logic. Thanks!